The long form of the periodic table is also known as the extended periodic table or the expanded periodic table. It includes all the elements known to date, arranged in increasing atomic number order and organized into periods (rows) and groups (columns) based on their chemical properties.
Salient features of the long form periodic table include:
1. Periods: The long form periodic table consists of several periods, each represented by a row. There are a total of seven periods. The period number indicates the energy level or shell occupied by the outermost electrons of the elements in that period.
2. Groups: The long form periodic table has numerous groups, also known as families or columns. The groups are numbered from 1 to 18. Elements within the same group have similar chemical properties due to their similar outer electron configurations.
3. Blocks: The long form periodic table is divided into blocks based on the types of orbitals being filled with electrons. These blocks are named s-block, p-block, d-block, and f-block.
4. Elements: The long form periodic table includes all the naturally occurring elements, as well as synthetic elements created in laboratories. It provides a comprehensive overview of all known elements, including their atomic number, symbol, atomic mass, and electronic configuration.
5. Lanthanides and Actinides: The f-block of the periodic table represents the inner transition metals known as lanthanides (in period 6) and actinides (in period 7). These elements are placed separately at the bottom of the periodic table to maintain its compact form.
6. Periodic Trends: The long form periodic table allows for a better understanding of periodic trends such as atomic radius, ionization energy, electron affinity, and electronegativity. These trends provide insights into the chemical behavior and reactivity of the elements.
7. Predictive Power: The periodic table's long form enables scientists to predict the properties of undiscovered elements and understand their placement within the table based on their expected electronic configurations.
8. Chemical Bonding and Reactions: The long form periodic table assists in understanding chemical bonding patterns, as elements with similar properties tend to form similar types of bonds. It also aids in predicting the reactions and chemical behavior of different elements and compounds.
Overall, the long form periodic table serves as a comprehensive and organized framework for studying the properties, trends, and relationships among elements, facilitating research, education, and advancements in the field of chemistry.